1. Field of the Invention
The present invention relates to a lubrication system for an internal combustion engine, and more particularly to a dry sump type lubrication structure.
2. Description of the Relevant Art
In a dry sump type lubrication structure, oil that has accumulated in a sump is sucked up by a scavenge pump and sent to an oil tank through an oil cooler, and oil in an oil tank is supplied to parts of the engine by a feed pump. This means that there is piping respectively between the oil cooler, the scavenge pump and the oil tank. As an example, Japanese Patent Laid-Open No. Hei-5-86829 discloses hoses, viewed from the side, that are fitted so as to run from the front over a cylinder and to the rear. This is achieved by plumbing a sending side hose from a rear upper surface of a transmission chamber to a catch tank above the cylinder, and plumbing a return side hose from the catch tank past the front of the cylinder to an oil tank below a crankcase, based on blow-by gas. Also, piping is made to intersect, and is gathered together at either the left or right side of the vehicle.
Also, Japanese Patent Laid-Open No. Hei-8-135419 discloses plumbing a sending side hose for sending oil sucked up by a scavenge pump from an oil pan provided in the central lower part of a crankcase from an upper surface of the crankcase behind the cylinder, above the cylinder and to an oil cooler in front of the cylinder, and, using the same route, piping a return side hose to an upper surface of a transmission.
In accordance with the background art, it is necessary to plumb a sending side hose and a return side hose. Such hoses are expensive and heavy. Further, the hoses must be ran over a long path length which increases the weight and costs of the vehicle. Accordingly, there is a need in the art for a lubrication structure which will shorten these oil hoses.